FIG. 1 shows a generic communication system comprising a transmitter device 1 and a receiver device 2. Specifically, in the example considered, the transmitter device 1 may transmit data to the receiver device 2 over a communication channel 3, which generally may be a cable, including also optical fibers, or a wireless communication channel. Generally, at the physical layer, the communication between the transmitter device 1 and the receiver device 2 may also use a plurality of parallel physical communication channels, e.g., a plurality of communication lines, and/or the communication may be unidirectional or bidirectional according to a given transmission protocol.
In regard to this, a telecommunication protocol is identified by a system of rules that allows two or more entities of a communication system to communicate between them in order to transmit data via a suitable variation of one or more physical quantities.
For example, FIG. 2 shows an example, wherein the transmitter device 1 is a remote control. Specifically, in the example considered, the remote control 1 comprises a wireless transmitter 10, such as an infrared (IR) photodiode. Similarly, the receiver device 2 may be an apparatus, such as a television, DVD-player, etc., comprising a wireless receiver 20, such as an IR receiver diode. Accordingly, in the example considered, the remote control 1 may transmit input data DI to the apparatus 2 by means of the wireless transmitter 10 and the wireless receiver 20. For example, the data DI may indicate a button having been pressed on the remote control 1.
Specifically, as shown in FIG. 3, a transmitter device 1 usually comprises a transmitter circuit 12 configured to drive the transmitter 10 in order to transmit input data DI, usually in accordance with a transmitter clock signal. In a complementary manner, the receiver device 2 comprises a receiver circuit 22 configured to receive the signal from the receiver 20 and determine the transmitted data DO.
In many applications efficient and ultra-low power communication solutions are required, e.g., because the receiver device 2 is powered via a battery 24.
However, ultra-low power transmission solutions may also be useful for apparatuses powered from the mains. For example, in order to receive a switch-on command from the remote control 1, the apparatus 2, such as a television, usually may not be switched-off completely but has to remain in a stand-by mode, in which the apparatus 2 is still consuming energy for powering the receiver circuit 22. Conversely, by using an ultra-low power receiver circuit 22, a small energy accumulator 24, such as a rechargeable battery, may be charged when the apparatus 2 is switched on and when the apparatus 2 is switched off: the energy accumulator 24 may be used to power the receiver circuit 22.
Moreover, ultra-low power communication solutions are also useful for receiver circuits 22, which may be powered through the communication channel 3. For example, in case of cables, some lines may directly transfer energy to the receiver. Conversely, in case of wireless communication, such as radio frequency (RF) or IR communications, an energy harvesting circuit 26 may be used. Specifically, such an energy harvesting circuit 26 may be configured to obtain the power supply for the receiver circuit 22 by extracting energy from the wireless communication, e.g., the radio wave or infrared radiation.